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Next: <a href="s390-Directives.html#s390-Directives" accesskey="n" rel="next">s390 Directives</a>, Previous: <a href="s390-Characters.html#s390-Characters" accesskey="p" rel="prev">s390 Characters</a>, Up: <a href="S_002f390_002dDependent.html#S_002f390_002dDependent" accesskey="u" rel="up">S/390-Dependent</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Instruction-syntax"></a>
<h4 class="subsection">9.38.3 Instruction syntax</h4>
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<a name="index-s390-instruction-syntax"></a>

<p>The assembler syntax closely follows the syntax outlined in
Enterprise Systems Architecture/390 Principles of Operation (SA22-7201)
and the z/Architecture Principles of Operation (SA22-7832).
</p>
<p>Each instruction has two major parts, the instruction mnemonic
and the instruction operands. The instruction format varies.
</p>
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<tr><td align="left" valign="top">&bull; <a href="s390-Register.html#s390-Register" accesskey="1">s390 Register</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Register Naming
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<tr><td align="left" valign="top">&bull; <a href="s390-Mnemonics.html#s390-Mnemonics" accesskey="2">s390 Mnemonics</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Instruction Mnemonics
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<tr><td align="left" valign="top">&bull; <a href="s390-Operands.html#s390-Operands" accesskey="3">s390 Operands</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Instruction Operands
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<tr><td align="left" valign="top">&bull; <a href="s390-Formats.html#s390-Formats" accesskey="4">s390 Formats</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Instruction Formats
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<tr><td align="left" valign="top">&bull; <a href="s390-Aliases.html#s390-Aliases" accesskey="5">s390 Aliases</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Instruction Aliases
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<tr><td align="left" valign="top">&bull; <a href="s390-Operand-Modifier.html#s390-Operand-Modifier" accesskey="6">s390 Operand Modifier</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Instruction Operand Modifier
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<tr><td align="left" valign="top">&bull; <a href="s390-Instruction-Marker.html#s390-Instruction-Marker" accesskey="7">s390 Instruction Marker</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Instruction Marker
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<tr><td align="left" valign="top">&bull; <a href="s390-Literal-Pool-Entries.html#s390-Literal-Pool-Entries" accesskey="8">s390 Literal Pool Entries</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Literal Pool Entries
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